On Wed, May 13, 2015 at 02:01:04PM +0800, Wanpeng Li wrote: > pull_dl_task can drop (and re-acquire) rq->lock, this means a stop task > can slip in, in which case we need to reschedule. This patch add the > reschedule when the scenario occurs. > > Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com> > --- > kernel/sched/deadline.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index e49b1e6..7d4c4fc 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1750,7 +1750,13 @@ static void switched_from_dl(struct rq *rq, struct > task_struct *p) > if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) > return; > > - if (pull_dl_task(rq)) > + /* > + * pull_dl_task() can drop (and re-acquire) rq->lock; this > + * means a stop task can slip in, in which case we need to > + * reschedule. > + */ > + if (pull_dl_task(rq) || > + (rq->stop && task_on_rq_queued(rq->stop))) > resched_curr(rq);
But, the waking of the stop task will already have done the preemption check and won (obviously). So the wakeup should already have done the resched_curr(). So why? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
